DESCRIPTION

The Unicode::UCD module offers a simple interface to the Unicode Character Database.

charinfo

use Unicode::UCD 'charinfo';
my $charinfo = charinfo(0x41);

charinfo() returns a reference to a hash that has the following fields as defined by the Unicode standard:

key
code code point with at least four hexdigits
name name of the character IN UPPER CASE
category general category of the character
combining classes used in the Canonical Ordering Algorithm
bidi bidirectional type
decomposition character decomposition mapping
decimal if decimal digit this is the integer numeric value
digit if digit this is the numeric value
numeric if numeric is the integer or rational numeric value
mirrored if mirrored in bidirectional text
unicode10 Unicode 1.0 name if existed and different
comment ISO 10646 comment field
upper uppercase equivalent mapping
lower lowercase equivalent mapping
title titlecase equivalent mapping
block block the character belongs to (used in \p{In...})
script script the character belongs to

If no match is found, a reference to an empty hash is returned.

The block property is the same as returned by charinfo(). It is not defined in the Unicode Character Database proper (Chapter 4 of the Unicode 3.0 Standard, aka TUS3) but instead in an auxiliary database (Chapter 14 of TUS3). Similarly for the script property.

Note that you cannot do (de)composition and casing based solely on the above decomposition and lower, upper, title, properties, you will need also the compexcl(), casefold(), and casespec() functions.

If supplied with an argument that can't be a code point, charblock() tries to do the opposite and interpret the argument as a character block. The return value is a range: an anonymous list of lists that contain start-of-range, end-of-range code point pairs. You can test whether a code point is in a range using the "charinrange" function. If the argument is not a known character block, undef is returned.

If supplied with an argument that can't be a code point, charscript() tries to do the opposite and interpret the argument as a character script. The return value is a range: an anonymous list of lists that contain start-of-range, end-of-range code point pairs. You can test whether a code point is in a range using the "charinrange" function. If the argument is not a known character script, undef is returned.

charblocks

use Unicode::UCD 'charblocks';
my $charblocks = charblocks();

charblocks() returns a reference to a hash with the known block names as the keys, and the code point ranges (see "charblock") as the values.

Blocks versus Scripts

The difference between a block and a script is that scripts are closer to the linguistic notion of a set of characters required to present languages, while block is more of an artifact of the Unicode character numbering and separation into blocks of (mostly) 256 characters.

For example the Latin script is spread over several blocks, such as Basic Latin, Latin 1 Supplement, Latin Extended-A, and Latin Extended-B. On the other hand, the Latin script does not contain all the characters of the Basic Latin block (also known as the ASCII): it includes only the letters, and not, for example, the digits or the punctuation.

For blocks see http://www.unicode.org/Public/UNIDATA/Blocks.txt

For scripts see UTR #24: http://www.unicode.org/unicode/reports/tr24/

Matching Scripts and Blocks

Scripts are matched with the regular-expression construct \p{...} (e.g. \p{Tibetan} matches characters of the Tibetan script), while \p{In...} is used for blocks (e.g. \p{InTibetan} matches any of the 256 code points in the Tibetan block).

Code Point Arguments

A code point argument is either a decimal or a hexadecimal scalar designating a Unicode character, or U+ followed by hexadecimals designating a Unicode character. In other words, if you want a code point to be interpreted as a hexadecimal number, you must prefix it with either 0x or U+, because a string like e.g. 123 will be interpreted as a decimal code point. Also note that Unicode is not limited to 16 bits (the number of Unicode characters is open-ended, in theory unlimited): you may have more than 4 hexdigits.

charinrange

In addition to using the \p{In...} and \P{In...} constructs, you can also test whether a code point is in the range as returned by "charblock" and "charscript" or as the values of the hash returned by "charblocks" and "charscripts" by using charinrange():

general_categories

The general_categories() returns a reference to a hash which has short general category names (such as Lu, Nd, Zs, S) as keys and long names (such as UppercaseLetter, DecimalNumber, SpaceSeparator, Symbol) as values. The hash is reversible in case you need to go from the long names to the short names. The general category is the one returned from charinfo() under the category key.

bidi_types

use Unicode::UCD 'bidi_types';
my $categories = bidi_types();

The bidi_types() returns a reference to a hash which has the short bidi (bidirectional) type names (such as L, R) as keys and long names (such as Left-to-Right, Right-to-Left) as values. The hash is reversible in case you need to go from the long names to the short names. The bidi type is the one returned from charinfo() under the bidi key. For the exact meaning of the various bidi classes the Unicode TR9 is recommended reading: http://www.unicode.org/reports/tr9/tr9-17.html (as of Unicode 5.0.0)

compexcl

use Unicode::UCD 'compexcl';
my $compexcl = compexcl("09dc");

The compexcl() returns the composition exclusion (that is, if the character should not be produced during a precomposition) of the character specified by a code point argument.

If there is a composition exclusion for the character, true is returned. Otherwise, false is returned.

casefold

use Unicode::UCD 'casefold';
my $casefold = casefold("00DF");

The casefold() returns the locale-independent case folding of the character specified by a code point argument.

If there is a case folding for that character, a reference to a hash with the following fields is returned:

key
code code point with at least four hexdigits
status "C", "F", "S", or "I"
mapping one or more codes separated by spaces

The meaning of the status is as follows:

C common case folding, common mappings shared
by both simple and full mappings
F full case folding, mappings that cause strings
to grow in length. Multiple characters are separated
by spaces
S simple case folding, mappings to single characters
where different from F
I special case for dotted uppercase I and
dotless lowercase i
- If this mapping is included, the result is
case-insensitive, but dotless and dotted I's
are not distinguished
- If this mapping is excluded, the result is not
fully case-insensitive, but dotless and dotted
I's are distinguished

If there is no case folding for that character, undef is returned.

For more information about case mappings see http://www.unicode.org/unicode/reports/tr21/

casespec

use Unicode::UCD 'casespec';
my $casespec = casespec("FB00");

The casespec() returns the potentially locale-dependent case mapping of the character specified by a code point argument. The mapping may change the length of the string (which the basic Unicode case mappings as returned by charinfo() never do).

If there is a case folding for that character, a reference to a hash with the following fields is returned:

The condition is optional. Where present, it consists of one or more locales or contexts, separated by spaces (other than as used to separate elements, spaces are to be ignored). A condition list overrides the normal behavior if all of the listed conditions are true. Case distinctions in the condition list are not significant. Conditions preceded by "NON_" represent the negation of the condition.

Note that when there are multiple case folding definitions for a single code point because of different locales, the value returned by casespec() is a hash reference which has the locales as the keys and hash references as described above as the values.

A locale is defined as a 2-letter ISO 3166 country code, possibly followed by a "_" and a 2-letter ISO language code (possibly followed by a "_" and a variant code). You can find the lists of those codes, see Locale::Country and Locale::Language.

A context is one of the following choices:

FINAL The letter is not followed by a letter of
general category L (e.g. Ll, Lt, Lu, Lm, or Lo)
MODERN The mapping is only used for modern text
AFTER_i The last base character was "i" (U+0069)

For more information about case mappings see http://www.unicode.org/unicode/reports/tr21/

namedseq()

If used with a single argument in a scalar context, returns the string consisting of the code points of the named sequence, or undef if no named sequence by that name exists. If used with a single argument in a list context, returns list of the code points. If used with no arguments in a list context, returns a hash with the names of the named sequences as the keys and the named sequences as strings as the values. Otherwise, returns undef or empty list depending on the context.

(New from Unicode 4.1.0)

Unicode::UCD::UnicodeVersion

Unicode::UCD::UnicodeVersion() returns the version of the Unicode Character Database, in other words, the version of the Unicode standard the database implements. The version is a string of numbers delimited by dots ('.').

Implementation Note

The first use of charinfo() opens a read-only filehandle to the Unicode Character Database (the database is included in the Perl distribution). The filehandle is then kept open for further queries. In other words, if you are wondering where one of your filehandles went, that's where.

BUGS

Does not yet support EBCDIC platforms.

AUTHOR

Jarkko Hietaniemi

Module Install Instructions

To install Unicode::UCD, simply copy and paste either of the commands in to your terminal